Direct fan to MH

[thinhvu]

I got AB 48'' fixture hang about 12'' above the tank. It produces heat to tha tank. So i set up a stand fan ( the one for household use) to reduce the heat. The fan is seated on the side and the direction of blow is toward the other side and between the top edge of the tank and the lower edge of the fixture. It really work out to lower the temp of the tank. I touch the fixture where the ballasts housed, it is kind of cool. But the UV glass is still hot. My question is that does it effect the efficience and performance of the MH?

Thanks in Advance.

 

[thinhvu]

^^^^^^^

 

[reefland]

Cooling the top part of the unit should be fine. Most people cool the tank directly though with a fan. I don't cool my Aquaspace light at all, but I do have a fan blowing on my center glass divider and a sump fan to cool the tank.

 

[Andy2]

The only problem a fan can have on MH performance is when the fan blows directly on the bulb. As long as the bulb is in a closed fixture, cooling the air between the tank and the fixture will only increase your evaporation rate, which will bring down the water's temperature.
Andy

 

[sdt5150]

Andy...

The only problem a fan can have on MH performance is when the fan blows directly on the bulb.

i have small ice cap fans blowing air directly on each of my MH bulbs. the bulbs are in a reflector, but not any sort of housing/casing. the air travels along the length of the bulb, blowing hot air out the back of the hood area. how is this effecting performance? let me know so i can make a change if necessary.

Thanks,
Doug

 

[Bubafat]

I have also heard that blowing air on a bulb will reduce its life. I tend to find this false as many bulbs are used for outdoor fixtures in weather conditions that vary. Now...on the other hand....I DO agree that blowing air on the bulb will change its color. Its a simple formula Max wavelength=2998/T (K) for a black body radiator (yes, i know, MH bulbs are not bbr, but its an estimate). So if you decrease the temp, you will increase the wavelength of the light, making it more yellow/red.

It could reduce the bulb's lifespan if the temp change was too high, and it caused the outer glass to crack due to the temp change but that is unlikely.

Bubafat

 

[xKEIGOx]

hemm.. as I have heard, the MH bulb are design to work on room temperature. So if it's constantly being cool down, the bulb might run dimmer in time.